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0:00
Hi, everyone.
Randy Nesse here, with a talk
about evolutionary psychiatry.
I've spent most of my
career as a professor of
psychiatry and psychology at
the University of Michigan.
Six years ago I moved to
Arizona State University
to start the Center for
Evolution in Medicine.
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What is evolutionary psychiatry?
It's a subsection of
evolutionary medicine,
and what is
evolutionary medicine?
It's simply using the basic
science of evolutionary biology
to better understand disease
and to better treat patients.
There's nothing
alternative about it.
It's just like using
genetics or anatomy.
The thing that's different is that we
have not been using evolutionary biology
either for medicine in general
or for psychiatry in particular.
0:48
There are two questions
to ask about a disease.
The traditional one is,
what's the mechanism?
What's broken?
How can we fix it?
A whole separate question is,
why does natural selection
not do a better job
of designing the system
so it wouldn't fail?
Why are we vulnerable?
That's the question that is at
the core of evolutionary medicine.
1:09
Why did natural selection leave
us vulnerable to disease?
This was the topic of a book
I wrote with George Williams
that got a lot of other people
interested in asking that question,
and here are some answers.
First of all, it has
limits, mutations.
It can't be prevented.
It can't start fresh.
That's the traditional
explanation for why
natural selection
leaves us vulnerable,
but there are others.
Another one is that natural
selection is just too slow
to protect us against
things that change fast,
especially pathogens
that evolve fast.
Nowadays, our societies evolve
much faster than we can,
leaving us vulnerable.
Thirdly, natural selection
doesn't maximize health.
This is very surprising
and disturbing.
It maximizes reproduction,
often at the expense of health.
All traits are
tradeoffs with costs,
so nothing can be
perfect in the body.
This idea is that evolutionary
medicine thinks everything is perfect,
but the opposite says that
nothing can be perfect.
Finally, a lot of defensive
responses like pain and fever
seem like they're
diseases or problems,
but they're useful responses.
